Seite - 1442 - in Book of Full Papers - Symposium Hydro Engineering

years subjected to erosion without any maintenance and repair. Under some particular geological conditions, this erosion may have become quite intensive.  Damaged or clogged bottom outlet which leads to the necessity of draining the reservoir only by means of an external temporary siphon.  With the time and without any maintenance, the spillway inlets of numerous small embankment dams have clogged by floating debris during relatively small flood events. Every time when there was flow in such spillways, additional amounts of debris were added. Thus, without cleaning the spillway inlet, the risk of dam crest overflow increases.  Non-maintained dam slopes with developed dense plant and tree cover. These slope conditions heavily complicate the access to the dam crest and all appurtenant structures. 3.3. PERFORMANCE PROBLEMS AFTER IMPACTS EXCEEDING NORMAL OPERATING CONDITIONS At several dams during flood events, the dam crest has been overtopped as well, Fig. 1 [5]. Fortunately, these dams retained their overall structural integrity, and no uncontrolled catastrophic release of the reservoir content occurred. However, the dam body in such cases was damaged, and all necessary repair works had to be carried out as soon as possible, for such dams to be able to further fulfill their basic operational requirements. Fig. 1 Damaged crest area after overflow Zone de couronnement endommagée après débordement 1442